(cross-posted from GD per Warpy's request)
Because of advancements in genetic science, we're able to get a better understanding when HIV possibly made the leap from monkeys to humans, by looking at viral mutations. Unlike human cells, HIV-1 only has 9 genes and doesn't have the mechanisms in place to make exact copies, so it is constantly mutating. We may never know the exact moment when this virus entered humans, but we are seeing research pointing to HIV being isolated and concentrated in the Congo Basin in Africa.
Hopefully, this type of research will start to put to rest the whole "HIV was created by the government" conspiracy that some like to hold on to, for whatever reason, in the face of what most research shows and is agreed upon.
By Elizabeth Pennisi
ScienceNOW Daily News
25 June 2008
MINNEAPOLIS, MINNESOTA--The human immunodeficiency virus (HIV-1) responsible for most of the AIDS cases in the world infected people approximately 100 years ago, more than 20 years earlier than previously believed, according to findings presented here this week at the Evolution 2008 meeting. Its lesser known cousin, HIV-2, jumped into humans decades later, from a monkey species that carried the virus for just a couple of hundred years, not the millions of years researchers had assumed, according to other research presented at the meeting.
The first clues that researchers were on the wrong track about the SIV that led to HIV-2 came last year. Researchers had assumed that because most monkey species infected with SIV don't get sick, the virus has been coevolving with the primates for millions of years, allowing the host and pathogen to peaceably coexist. If that were the case, the branching of the monkey family tree should match the branching of the SIV tree. But last year, University of Arizona, Tucson, graduate student Joel Wertheim, his adviser, Michael Worobey, and colleagues found that not to be the case for the African green monkey and its SIV. "The work suggested that the virus was not millions of years old," Wertheim said at the meeting.
(snip)
Wertheim used a sophisticated computer program to build a family tree based on the degree of differences among the sequences. The analysis also determined when the various strains--branches on this tree--appeared. The sooty mangabey caught its first SIV in 1808, and it jumped into humans 125 years later to become HIV-2, he reported at the meeting.
(snip)
By comparing the two sequences with more recent ones, Gemmel was able to show that HIV-1 first entered humans about 1908, not 1931, as earlier analyses with just the 1959 sample found. Her analysis also indicates that the virus existed in low levels in humans until the middle of the 20th century. "That matches the rise of population centers," Gemmel explained, suggesting that urbanization around that time paved the way for the AIDS epidemic.
http://sciencenow.sciencemag.org/cgi/content/full/2008/625/1
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